Dr. Graham's long term goal is to understand how the cell assembles and maintains the ordered arrangement of compartments that comprise the Golgi complex, and how this structure contributes to the function of this essential organelle. The specific aims are: (1) to continue to define the compartmental organization of the yeast Golgi complex and the factors required for protein transport between Golgi compartments; (2) to decipher the localization signal(s) within a resident protein of the yeast Golgi complex, the Mnn1 protein (Mnn1p); (3) to isolate mutants that exhibit a defect in the Golgi localization of the Mnn1p; and (4) to isolate gene fragments that encode sorting information specific to the yeast secretory pathway.